Extrusion apparatus for manufacture of thermoplastic pipe

ABSTRACT

IMPROVED APPARATUS FOR THE MANUFACTURE OF PLASTIC PIPE AND TUBING INCLUDING A FORMING DIE, A SIZING PLATES, A WATER COOLING BATH CONTAINED IN A CLOSED CHAMBER WHEREIN A PARTIAL VACUUM IS MAINTAINED, THE IMPROVEMENT WHICH CONSISTS IN PROVISION OF A HOLLOW TUBULAR COOLING ELEMENT ATTACHED TO OR UNITARY WITH THE SIZING PLTAE AROUND THE ENTIRE RIM OF THE SIZING ORIFICE TO FORM A CHAMBER THROUGH WHICH A COOLANT IS CONTINUOUSLY CIRCULATED. THIS ELEMENT IS PARTICULARLY CHARACTERIZED BY PRESENTING A SMOOTH, COOLED, ROUNDED EDGE CIRCULAR SIZING ORIFICE TO PREVENT FORMATION OF DEFECTS IN THE OUTER SURFACE OF THE PIPE WHICH MIGHT OTHERWISE ARISE FROM ADHESION OF THE MOLTEN PLASTIC TO THE METAL SURFACE OF THE SIZING ORIFICE, OR FROM IRREGULARITIES IN THE SURFACE OF AN UNROUNDED ORIFICE, THUS ELIMINATING THE NEED FOR EMPLOYING OF ANY OF TYPE OF LUBRICANT AT THE SIZING ORIFICE.

DEFENSIVE PUBLIGATIUN UNITED STATES PATENT OFFICE Published at therequest of the applicant or owner in accordance with the Notice of Dec.16, 1969, 869 0.G. 687. The abstracts of Defensive Publicationapplications are identified by distinctly numbered series and arearranged chronologically. The heading of each abstract indicates thenumber of pages of specification, including claims and sheets ofdrawings contained in the application as originally filed. The files ofthese applications are available to the public-for inspection andreproduction may be purchased for 30 cents a sheet.

Defensive Publication applications have not been examined as to themerits of alleged invention. The Patent Ofiice makes no assertion as tothe novelty of the disclosed subject matter;

PUBLISHED JULY 25, 1972 T900,024 EXTRUSION APPARATUS FOR MANUFACTURE OFTHERMOPLASTIC PIPE Edward R. Hollander, Jr., 124 Bloomingdale Pike, Apt.27, Kingsport, Tenn. 37 660 Filed June 1, 1971, Ser. No. 148,566

Int. Cl, 329d 23/04 US. Cl. 18-14 A 1 Sheet Drawing. 10 PagesSpecification Improved apparatus for the manufacture of plastic pipe andtubing including a forming die, a sizing plate, a water cooling bathcontained in a closed chamber wherein a partial vacuum is maintained,the improvement Which consists in provision of a hollow tubular coolingelement attached to or unitary with the sizing plate around the entirerim of the sizing orifice to form a chamber through which a coolant iscontinuously circulated. This element is particularly characterized bypresenting a smooth, cooled, rounded edge circular sizing orifice toprevent formation of defects in the outer surface of the pipe whichmight otherwise arise from adhesion of the molten plastic to the metalsurface of the sizing orifice, or from irregularities in the surface ofan unrounded orifice, thus eliminating the need for employment of anytype of lubricant at the sizing orifice.

July 25, 1972 E. R. HOLLANDER, JR T900924 EXTRUSION APPARATUS FORMANUFACTURE OF THERMOPLASTIC PIPE Filed June 1 EDWARD R. HOLLANDER, JR

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